Chronic Obstructive Pulmonary Disease (COPD) is a common chronic airway disease leading to alveoli damage (emphysema) and long-term inflammation of small airways (chronic bronchitis). COPD patients are among those worst affected by infections such as COVID-19. Treatment of COPD includes inhalation of drug aerosols for which it is crucial to be able to achieve effective delivery to diseased regions inside the lungs. Transport and deposition of inhaled pollutant or therapeutic aerosols inside the human airways is a complex phenomenon which depends on several factors such as inhalation maneuver, airway morphology and the aerosol properties.  In silico methods provide a non-invasive tool that can be used to study the characteristics of airflow and aerosol transport at the finer structures in the lung depths that would otherwise be inaccessible. This project aims to develop 3D in silico lung models for COPD patients. Upper airway geometries of COPD patients are reconstructed using data from computed tomography scans. The chronic bronchitis component of COPD is accounted with airway narrowing in simplified models of the deep conducting generations. Development of emphysematous acini models is based on existing in vivo nanoparticle measurements of deposition, which can characterize dimensions in the alveolar airspaces. The developed models will be used to study airflow and aerosol deposition at various stages of COPD severity and investigate how these are altered compared to the healthy lung. The findings of this project can be used to assess health risks from exposure to xenobiotic aerosols as well as guide inhalation therapies and contribute in improving the efficacy of inhaled medications for COPD patients.